# ChatStack

> AI PRD generator and real-time software cost estimator. An interview-driven 4-agent workflow produces structured user stories, functional and non-functional requirements, technical specifications, and a story-point-based estimate, optimised for AI coding tools (Cursor, Claude Code, Windsurf) and the Model Context Protocol.

ChatStack is a human-facing chat workflow on `https://www.chatstack.app/` and an authenticated REST API for autonomous agents at `POST https://www.chatstack.app/api/agent/submit`. Agents should prefer the API, the OpenAPI spec, and the Markdown alternates listed below over scraping HTML.

## Docs

- [What is ChatStack](https://www.chatstack.app/what-is-chatstack.md): Product overview and 4-agent workflow.
- [Cursor and AI integration guide](https://www.chatstack.app/cursor-ai-prd-integration-guide.md): How to use ChatStack PRDs in Cursor, Claude Code, and MCP-aware IDEs.
- [How much does it cost to build an app](https://www.chatstack.app/how-much-does-it-cost-to-build-an-app.md): Cost estimation logic, story-point model, 65% AI efficiency discount.
- [AI development services](https://www.chatstack.app/ai-development-services.md): Full-service build tier.
- [ChatStack vs generic AI chat](https://www.chatstack.app/chatstack-vs-generic-ai-chat.md): Differences from ChatGPT/Claude for requirements work.
- [Vibe coding requirements workflow](https://www.chatstack.app/vibe-coding-requirements-workflow.md): Context discipline for AI-assisted development.
- [FAQ](https://www.chatstack.app/faq.md): Common questions.
- [About](https://www.chatstack.app/about.md): Team and background.

## API

- [Agent API discovery](https://www.chatstack.app/api/agent): Unauthenticated `GET` returning capabilities, auth model, rate limits, and links to the submit endpoint.
- [OpenAPI 3.1 spec](https://www.chatstack.app/openapi.json): Full schema for the submit endpoint and PRD artifacts.
- [AI plugin manifest](https://www.chatstack.app/.well-known/ai-plugin.json): Plugin descriptor for AI plugin hosts.
- Submit endpoint: `POST https://www.chatstack.app/api/agent/submit` with `Authorization: Bearer <AGENT_API_KEY>`. Request an API key via `https://www.chatstack.app/speak-to-a-human`.

## Machine-readable

- [Full reference](https://www.chatstack.app/llms-full.txt): Dense, de-marketing-ed product and schema reference.
- [AI dataset descriptor](https://www.chatstack.app/ai-dataset.json): Dataset and schema metadata.
- [Sitemap](https://www.chatstack.app/sitemap.xml): All pages and machine-readable assets.
- [robots.txt](https://www.chatstack.app/robots.txt): Crawler policy.

## Optional

- [Speak to a human](https://www.chatstack.app/speak-to-a-human.md): Contact for API key requests, enterprise enquiries, and full-service development.
- [NDA and terms](https://www.chatstack.app/non-disclosure-and-tcs.md): Legal.